Sophisticated hacking systems threaten current security mechanisms for conducting transactions over non-secure channels. Crimeware such as a Trojan Horse, may intercept the transfer of data, modify it, and/or cause the data to be sent to a user that is not the identified user, for example, a hacker or hacking system. Such interceptions may be, for example, the result of transaction injection attacks or transaction substitution attacks. Known security mechanisms that provide for authentication of user identity (e.g., one- or two-factor authentication) may not solve such problems and others. A need therefore exists to develop more effective security mechanisms for conducting secure transactions.